Multiple-Input Multiple-Output (MIMO) technology is a wireless technology that uses multiple transmitters and receivers to transfer more data at the same time. MIMO technology takes advantage of a natural radio-wave phenomenon called multipath. With multipath, transmitted information bounces off walls, ceilings, and other objects, reaching the receiving antenna multiple times via different angles and at slightly different times. In the past, multipath caused interference and slowed down wireless signals. MIMO technology can take advantage of multipath behavior by using multiple, smart transmitters and receivers with an added spatial dimension, to dramatically increase performance and range. In order to implement MIMO, communication devices (e.g., access point devices, station devices, or the like) are configured to support MIMO. For instance, a station device (e.g., a mobile device) and/or an access point (AP) device need to support MIMO. In some scenarios, for optimal performance and range, both the station device and the AP device can support MIMO. In MIMO operation, the AP device can estimate a communication channel in the upstream link (or uplink (UL)) by using specific information (e.g., long training field (LTF) sequences) received from stations devices. The particular design for the communication of such information can determine the efficiency and/or quality of channel estimation.